Conventionally, a mobile phone comprises control, audio, power, input, output, and wireless receiving circuits. The mobile phone is designed to enable both distant persons having a mobile phone to communicate each other. The circuits are enclosed in a housing as a whole so as to facilitate carrying the mobile phone and using the same. Size of mobile phone is getting smaller and weight thereof is getting lighter as both material science and electronics industry make progress significantly in recent years. Thus, even children or women are able to carry a mobile phone.
However, it is not easy for a user to know whereabouts of a missing mobile phone since size of the mobile phone is getting smaller. It is thus often that a user cannot find his or her mobile phone placed in a location just several tens minutes ago. It is also often that a user forgot whereabouts of his or her mobile phone after placing the mobile phone in a location a relatively long period of time ago. This is because a mobile phone typically does not have a distinct appearance. Further, there is no way for a user to audibly know whereabouts of a missing mobile phone by dialing its number since the mobile phone is typically in an inoperative state. Thus, there is no way for a user to find the missing mobile phone. And in turn, it may cause environmental pollution since there is no way to recycle the mobile phone if it is no more useful. Further, it may bear a great financial burden upon a user since he or she has to buy a new mobile phone. Thus, it is desirable to provide a novel system for enabling a user to know whereabouts of his or her missing mobile phone in order to overcome the inadequacies of the prior art.